Electronic display devices display color images, ideally, by a combination of three primary colors: red, blue, and green. To display images with clearer colors, it has been devised to equip the devices with filters having a color compensating function.
Squarylium compounds have been known as coloring compounds for filters having a color compensating function (refer to Published Japanese Unexamined Patent Application No. 345059/2000). A specific squarylium compound has been known as a colorant for an electronic display device filter that can selectively shield the light having a wavelength of about 480 to about 520 nm (refer to Published Japanese Unexamined Patent Application No. 97383/2002).